Image forming device and method for transferring a toner image onto a recording medium

ABSTRACT

An image forming device and an image forming method for transporting a toner image on an endless belt shaped toner image transporting member. The toner image transporting member is supported by a plurality of rollers and is stretched out and made rotatable in the same direction as the recording medium is transported. The colored toner is transported on the outside of the toner image transporting member and is transferred onto stationary recording medium by an opposed image transferring roller while the rotation of the toner image transporting member is suspended. The image transferring process is repeated for the required number of colors.

This application is a U.S. National Phase Application of PCTInternational Application PCT/JP97/03560.

FIELD OF THE INVENTION

The present invention relates to an image forming device and an imageforming method for transferring toner images directly onto a printingpaper from a toner image transporting member not via the medium of anintermediate image transferring member and the like.

BACKGROUND OF THE INVENTION

In recent years an image forming device using a toner system asexemplified by a laser printer has been widely used to make it possibleto produce clear images with excellent resolution. Among the imageforming devices using a toner system, as mentioned in the above, thereare signs of change with the advent of models that can handle colorimages.

A description will be made of a prior art image forming device forforming color images.

FIG. 9 is a perspective view of a prior art image forming device that isin a state of performing an image transferring process. In FIG. 9, aphotosensitive belt 101 is one form of the toner image transportingmembers and is coated with a layer of an organic photoconductivematerial on the surface thereof. The photosensitive belt 101 thusprepared rotates in the direction indicated by an arrow, thereby animage in each respective color out of the four primary colors, i.e.,cyan, magenta, yellow and black, being formed in succession. Next, aseries of the steps for forming color images will be described.

The photosensitive belt 101, the surface of which is uniformly chargedto about -600 V by a charging means, is irradiated with laser lightaccording to image signals from a light exposure making means 102constructed by such an optical system as a laser irradiation unit, apolygon mirror and the like. The surface potential of the area exposedto the laser light is raised to around -100 V and an electrostaticlatent image is formed on the surface of the photosensitive belt 101. Animage developing means 103 is formed of four sections for eachrespective primary color, i.e., an image developing means 103C for cyan,an image developing means 103M for magenta, an image developing means103Y for yellow and an image developing means 103B for black, eachperforming an image developing process for one color out of the fourprimary colors by the use of primary color toner contained in eachrespective section of the above.

For example, when an image developing process for an image in cyan isperformed, a development roller of the image developing means 103Cattached with negatively charged toner is pressed onto thephotosensitive belt 101 to convert the electrostatic latent image into avisible image, transferring toner onto the surface of the photosensitivebelt 101 in an area, where the electrostatic latent image has beenformed. Thus, a toner image in cyan is formed. Then, the toner image incyan formed on the photosensitive belt 101 is transferred onto anintermediate image transferring member 104. After the above imagetransferring, the toner that has remained on the surface of thephotosensitive belt 101 is eliminated by a cleaning means.

A series of the foregoing steps are repeatedly performed for cyan,magenta, yellow and black in this order and a colored toner image 105with the four primary colors combined is formed on the intermediateimage transferring member 104. Then, the toner image 105 formed on thesurface of the intermediate image transferring member 104 is transferredonto a printing paper 107 via pressure from the image transferringroller 106. At this time, the intermediate image transferring member 104is rotated in the direction, in which the printing paper 107 istransported.

After the image transferring, the toner having remained on theintermediate image transferring member 104 is eliminated by a cleaningmeans. Finally, an image fixing means 108 places the printing paper 107transferred with the toner image 105 between a pressure applying roller109 and a heat applying roller 110 provided with a heat source inside,thus having a color image fixed onto the printing paper 107 by fusingtoner particles into place.

However, the prior art image forming device as described in the aboverequires without fail the intermediate image transferring member 104 inorder to form a color image and the size of the device is made large andthe mechanism is made complex, resulting in an increase of componentcounts just because of the existence of the intermediate imagetransferring member 104, thereby making it difficult to reduce the sizeof the image forming device.

DISCLOSURE OF THE INVENTION

The object of the present invention is to deal with the foregoingproblem and to realize an image forming device with a smaller main bodyby eliminating an intermediate image transferring member.

In order to achieve the above object, the image forming device of thepresent invention comprises:

a plurality of rollers;

a rotatable and loop-like belt shaped toner image transporting beltsupported by the plurality of rollers;

colored toner for the toner image transporting belt to transport acolored toner image; and

an opposed image transferring roller installed on the inner side of theloop-like belt shaped toner image transporting belt, in which the tonerimage transporting belt is rotatable in the same direction as a recordmedium in transit is transported; and

the color toner image which is transported on the outer surface of thetoner image transporting belt is transferred onto the record medium bymeans of the opposed image transferring roller while the rotation of thetoner image transporting belt is suspended.

Another image forming device of the present invention comprises:

(a) a loop-like belt shaped toner image transporting belt to transport atoner image;

(b) a plurality of rollers to support and rotate the toner imagetransporting belt;

(c) a toner attaching means to have colored toner attached on the outersurface of the toner image transporting belt and have a toner imagetransported; and

(d) an opposed transferring roller installed on an inner side of thetoner image transporting belt in such a way as the toner imagetransporting belt is pressed down on the record medium and also mademovable.

An image forming method of the present invention comprises the steps of:

(a) forming a first colored toner image of a plurality of colored tonerimages, each having a color different from one another, on a surface ofa rotatable loop-like toner image transporting belt; and

(b) forming a first composite color image on the surface of the recordmedium by moving the toner image transporting belt by rolling with apressing force applied thereto to transfer the first colored toner imagefrom the toner image transporting belt to the record medium while arotation of the toner image transporting belt being suspended.

According to the structure as described in the above, a small sizedimage forming device is realized and further the toner imagetransferring efficiency is enhanced, thereby enabling the realization ofenriched images.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic diagram of an image forming device in an exemplaryembodiment of the present invention.

FIG. 2 is a perspective view of the transferring process of an imageforming device in an exemplary embodiment of the present invention.

FIG. 3 is another perspective view of the transferring process of animage forming device in an exemplary embodiment of the presentinvention.

FIG. 4 is a diagrammatic sketch showing the state of transferring of animage in an exemplary embodiment of the present invention.

FIG. 5 is another diagrammatic sketch showing the state of transferringof an image in an exemplary embodiment of the present invention.

FIG. 6 is still another diagrammatic sketch showing the state oftransferring of an image in an exemplary embodiment of the presentinvention.

FIG. 7 is still another diagrammatic sketch showing the state oftransferring of an image in an exemplary embodiment of the presentinvention.

FIG. 8 is a diagrammatic sketch of the image fixing means of an imageforming device in an exemplary embodiment of the present invention.

FIG. 9 is a perspective view showing the state of transferring of aprior art image forming device.

PREFERRED EXEMPLARY EMBODIMENT OF THE INVENTION

A description will be made on an exemplary embodiment of the presentinvention in the following:

If a brief description is made on an exemplary embodiment of the presentinvention, every time when an image developing process for one color isfinished by each respective image developing means for a plurality ofcolors, the rotation of a toner image transporting member is suspendedand an opposed image transferring roller is moved so as to rub a tonerimage of the toner image transporting member against a stationaryprinting paper, thereby transferring a toner image of a specific coloronto the printing paper directly. This transferring process is repeatedfor each respective color by the number of times that correspond to thenumber of kinds of colors used to form a colored toner image on theprinting paper. Then, the colored toner image on the printing paper isfixed by an image fixing means.

Accordingly, the bulky intermediate transferring member, which has beenneeded without fail in a prior art image forming device, can beeliminated, leading to simplification of the structure itself with aresulting reduction in size of the device. Since the image transferringefficiency per one time of toner transferring is about 90% and a tonerimage is transferred from the toner image transporting member directlyto the printing paper without the intermediate image transferringmember, thereby reducing the steps needed in toner image transferring.As a result, the reduction in the image transferring efficiency of tonercan be eventually prevented.

Next, a detailed description will be made on an exemplary embodiment ofthe present invention with reference to FIG. 1 to FIG. 8.

FIG. 1 is a schematic diagram of an image forming device in an exemplaryembodiment of the present invention. FIG. 2 is a perspective view of thego transferring process of an image forming device in an exemplaryembodiment of the present invention. FIG. 3 is another perspective viewof the go transferring process of an image forming device in anexemplary embodiment of the present invention. FIG. 4 to FIG. 7 showdiagrammatic sketches of the state of transferring of an image in anexemplary embodiment of the present invention. FIG. 8 is a diagrammaticsketch of the image fixing means of an image forming device in anexemplary embodiment of the present invention.

In FIG. 1 to FIG. 3, an endless loop-like belt shaped toner imagetransporting member 11 formed of a photosensitive belt, the surface ofwhich is coated with a layer of an organic photoconductive material, isinstalled by stretching in the same direction as a printing paper 7serving as a record medium is transported by means of a plurality ofrollers such as a supporting roller 12, a displacement roller 13, anopposed transferring roller 14 and the like, and a toner image of aprimary color is formed on the surface of the toner image transportingmember 11 by having the toner image transporting member 11 rotated inthe direction indicated by an arrow "X". A charging means 15, a cleaningmeans 16, a discharging means 17 and the like are arranged surroundingthe toner image transporting member 11. Furthermore, in the surroundingsof the toner image transporting member 11 are arranged a toner attachingmeans 18 for a plurality of colors, including a cyan image developingmeans 18C, a magenta image developing means 18M, a yellow imagedeveloping means 18Y and a black image developing means 18B, in such away as each respective image developing means can move into contact withor off the toner image transporting member 11 and also in the rotationaldirection of the toner image transporting member 11. The imagedeveloping means 18C, 18M, 18Y and 18B for respective colors have anexclusive image developing roller 18r, respectively. In addition, alight exposure making means 2 for irradiating laser light is locatedabove the toner image transporting member 11. In this exemplaryembodiment of the invention, the description will be made of a casewhere laser light is used as a typical light source for the lightexposure making means 2, but light from on LED or on LCD instead oflaser light can also be used in the light exposure making means 2. Whenthe toner image transporting member 11 is rotated in the same directionas indicated by the arrow "X" in FIG. 1 and as the printing paper 7 istransported, the area on the toner image transporting member 11 that haspassed the charging means 15 is uniformly charged to about -600 V. Thelight exposure making means 2 irradiates the surface of the toner imagetransporting member 11 with laser light for each respective coloraccording to the image signals for the four primary colors, i.e., cyan,magenta, yellow and black. Then, the potential of the area irradiated bythe laser light is increased to around -100 V and an electrostaticlatent image for each respective primary color is formed on the surfaceof the toner image transporting member 11. Only one image developingmeans of the toner image attaching means 18 for the plurality of colors,which corresponds to the laser light irradiated, is brought into contactwith the foregoing area, where the above electrostatic latent image hasbeen formed, and a toner image of a specific color, which has now becomevisible, is formed on the toner image transporting member 11 by havingthe image developing roller 18r pressed down on the toner. This processis repeated for each respective color involved, thereby toner images ofdifferent colors being developed one after another.

As shown in FIG. 1 to FIG. 3, the toner attaching means 18 for aplurality of colors has four image developing means 18C, 18M, 18Y and18B corresponding to each respective primary color involved, and each ofthe four image developing means can move into contact with or off thetoner image transporting member 11 as described before. However, it isalso possible for the image developing means to use a method of jumpingimage development, whereby the image developing is performed without anycontact with the toner image transporting member 11 and the like. Thus,according to the present invention, the "moving into contact" as used inthe developing means' capability of moving into contact or off the tonerimage transporting member 11 should be interpreted as including themeaning of "moving into the vicinity". A toner image of each of the fourprimary colors, i.e., cyan, magenta, yellow and black, is formed on eachrespective image developing roller 18r by the use of the toner ofprimary colors as carried in each of the cyan image developing means18C, magenta image developing means 18M, yellow image developing means18Y and black image developing means 18B.

Incidentally, as widely known, a black color can be produced from thetoner of three primary colors of cyan, magenta and yellow withoutrelying on the black toner and therefore it is possible for the tonerattaching means 18 for a plurality of colors to be formed of three imagedeveloping means of cyan image developing means 18C, magenta imagedeveloping means 18M and yellow image developing means 18Y Also, inaddition to the four primary colors of cyan, magenta, yellow and black,image developing means for such relatively frequently used colors aslight cyan, light magenta and the like can be used, thereby providing asmany as six different colors and the like to the toner attaching means18 for a plurality of colors.

In the exemplary embodiment as described in the above, the tonerattaching means 18 for a plurality of colors is installed on the mainbody of the image forming device by the number as required according tothe variety of colors used, but it is also possible for the imageforming device to install only one image developing means by employing adetachable/attachable image developing means holder, thereby allowing auser of the image forming device to form a colored toner image byexchanging the toner attaching means 18 for a plurality of colorswhenever it becomes necessary.

Furthermore, in the foregoing arrangement, where a user exchanges thetoner attaching means 18 for a plurality of colors, it is also possiblefor the user to form a monochrome toner image such as a black and whitetoner image and the like without exchanging the toner attaching means 18for a plurality of colors.

When a toner image for one color is transferred onto a printing paper 7,the printing paper 7 is made stationary on a transferring plate 19 andalso the rotation of the toner image transporting member 11 is suspendedas shown in FIG. 2 and FIG. 3. The area of the toner image transportingmember 11, where a toner image for one color has been formed, is presseddown onto the printing paper 7 by rolling the opposed transferringroller 14 on the back side of the toner image transporting member 11 toperform an transferring process of the toner image, and then the tonerimage transporting member 11 is displaced by an extent corresponding toone step of processing from the left end or right end in the reverseddirection. At this time, the transferring ended area "Z" of the tonerimage transporting member 11, where transferring of a toner image forone color has been finished, is taken off, step by step, from theprinting paper 7 with the passing of the opposed transferring roller 14.During the step of image transferring, a positive voltage is beingapplied to the transferring plate 19, on which the printing paper 7 isplaced; thereby attracting the negatively charged toner image andpeeling off the same from the surface of the toner image transportingmember 11 and having the toner image transferred onto the printing paper7. This process of transferring the toner image from the toner imagetransporting member 11 is performed not only in the go direction asdescribed in the above (see FIG. 2) but also can be performed in thereturn direction. (See FIG. 3) At this time, the toner imagetransporting member 11 is displaced on the printing paper 7 in the samedirection as the printing paper 7 is transported.

As shown in FIG. 1, the cleaning means 16 eliminates the toner that hasremained on the surface of the toner image transporting member 11 by theuse of a cleaning blade or a cleaning brush and reclaim the toner forrecycling, thus cleaning the surface of the toner image transportingmember 11 physically. The discharging means 17 neutralizes the negativecharges that have remained on the surface of the toner imagetransporting member 11 after the residual toner was removed, thuscleaning the surface of the toner image transporting member 11electrically. However, the installation of the discharging means 17 isnot mandatory.

As shown in FIG. 2, after the image transferring for the first one colorportion has been finished, the same process is repeated for theremaining colors. As shown in FIG. 3, a colored toner image 5 formed ofthe four primary colors is finally formed on the printing paper 7, andupon completion of the image transferring for the four colors theprinting paper 7 is transported to an image fixing means 8.

Accordingly, the present exemplary embodiment makes it possible for thetoner image on the toner image transporting member 11 to be directlytransferred onto the printing paper 7 for each respective color, thuseliminating the need for an intermediate image transferring member incontrast to the prior art example. As a result, the mechanism involvedis made simple and the main body of the image forming device can be madesmall in size. The image transferring efficiency for each transfer oftoner image is about 90% at present, and the ultimate image transferringefficiency of 90% is being maintained by the direct image transferringperformed from the toner image transporting member 11 onto the printingpaper 7 without the use of an intermediate image transferring member.With a prior art image forming device, a needed two-time imagetransferring operation with a 90% image transferring efficiency for eachtime has resulted in a reduction to 81% in the ultimate imagetransferring efficiency. In contrast, the darkness of an image formed ona printing paper 7 according to an exemplary embodiment of the presentinvention has obviously been increased greatly.

An image forming method for forming a colored toner image onto astationary printing paper 7 starts with the state as illustrated in FIG.4, in which a first step of transferring a toner image in {cyan} onlytakes place. Next, as illustrated in FIG. 5, a second step oftransferring a toner image in {magenta} takes place, thereby the tonerimage in magenta being superimposed on the toner image in cyan on theprinting paper 7. Similarly, a third step of transferring a toner imagein {yellow} takes place, resulting in a superimposing of the toner imagein yellow upon the images in cyan and magenta, as illustrated in FIG. 6.Finally, a fourth step of transferring a toner image in {black} takesplace, thus forming a colored toner image on the printing paper 7 withthe toner images formed in {cyan, magenta, yellow and black}, asillustrated in FIG. 7.

After having repeated the foregoing steps, the printing paper 7 istransported slowly to the image fixing means 8, in which the printingpaper 7 with a toner image transferred thereon is sandwiched between apressure applying roller 9 and a heat applying roller 10 with a heatsource provided inside, thereby having the toner image fixed on theprinting paper 7 by melting the toner particles into place, asillustrated in FIG. 3.

It is also possible to employ an image fixing means as shown in FIG. 8.In FIG. 8, an image fixing means 20 has a heat source 21 and a firstreflecting plate 22, and there is a second reflecting plate 23 installedunderneath the image fixing means 20. This structure allows the thermalefficiency to be enhanced and the toner to be fixed in a non-contactmanner.

As described in the above, a series of the image forming steps come toan end.

In the present exemplary embodiment, a photosensitive image developingmeans has been employed to form a toner image transporting member, butin place of the photosensitive image developing means (a) aheat-sensitive image developing means, by which a toner image is formedthrough developing an electrostatic latent image by the use of a heatsource, or (b) a wood-block print like image forming means, by whichtoner is applied all over the surface of a toner transporting member bythe use of an image developing means and then the toner is blown awayfrom the toner transporting member to have a toner image formed as if awood-block image is carved, can also be adopted.

INDUSTRIAL APPLICABILITY

According to the structure disclosed by the present invention, it ismade possible for an image forming device to eliminate a bulkyintermediate image transferring member that was indispensable to a priorart image forming device. As a result, the construction of the imageforming device itself has become simple, thus making it possible toreduce the size of the image forming device. The image transferringefficiency for each toner transferring process is about 90% and theimage forming method of the present invention does not employ anintermediate image transferring member since a toner image is directlytransferred from a toner image transporting member onto a printing paperwith a resulting reduction in the number of image transferring steps,thereby preventing the degradation of the ultimate toner imagetransferring efficiency and contributing to marked enhancement of thedarkness of the printed image.

What is claimed is:
 1. An image forming device comprising:a plurality ofrollers; a loop-like belt shaped toner image transporting belt supportedby said plurality of rollers; colored toner to have colored toner imagestransported on said toner image transporting belt; and an opposed imagetransferring roller installed on an inner side of said loop-like beltshaped toner image transporting belt, wherein said toner imagetransporting belt is made rotatable in the same direction as a recordmedium in transit is transported and said colored toner imagestransported on the outer surface of said toner image transporting beltare transferred onto said record medium by the use of said opposed imagetransferring roller while the rotation of said toner image transportingbelt being suspended.
 2. The image forming device according to claim1,further comprising an image fixing means for fixing said colored tonerimage transferred onto said record medium.
 3. The image forming deviceaccording to claim 1,wherein said record medium is a printing paper. 4.The image forming device according to claim 1,wherein said toner imagetransporting belt has at least one image developing means selected fromthe group consisting of a photosensitive image developing means, aheat-sensitive image developing means and a wood-block print type imagedeveloping means.
 5. An image forming device comprising:(a) a loop-likebelt shaped toner image transporting belt for transporting a tonerimage, set up in such a way as rotatable in the same direction as arecord medium in transit is transported; (b) a plurality of rollers thatsupport and make rotatable said toner image transporting belt; (c) atoner attaching means for having colored toner attached and having acolored toner image transported on the outer surface of said toner imagetransporting belt, where said toner attaching means moves toward saidtoner image transporting belt; and (d) an opposed image transferringroller installed on the inner side of said toner image transporting beltso as to have said toner image transporting belt pressed onto saidrecord medium and to make the same movable, and provided with thefunction of transferring said colored toner image, which has beentransported on said toner image transporting belt, onto said recordmedium.
 6. The image forming device according to claim 5,wherein whilethe rotation of said toner image transporting belt being suspended saidopposed image transferring roller presses said toner image transportingbelt onto said record medium while moving and said colored toner imageis transferred onto said stationary record medium.
 7. An image formingdevice of claim 5 wherein said toner attaching means move toward saidtoner image transporting belt one after the other.
 8. An image formingdevice comprising:(a) a loop-like belt shaped toner image transportingbelt for transporting a toner image, said toner image transporting beltbeing installed so as to be rotatable in the same direction as a recordmedium is transported; (b) a plurality of rollers that support and makerotatable said toner image transporting belt; (c) a plurality of tonerattaching means that moves toward said toner image transporting beltalong a rotational direction of said toner image transporting belt so asto have a plurality of colored toner images, each of which has a colordifferent from others, attached and transported on an outer surface ofsaid toner image transporting belt, for having the plurality of coloredtoner images transported; and (d) an opposed image transferring rollerinstalled on the inner side of said toner image transporting belt so asto have said toner image transporting belt pressed onto said recordmedium and to make the same movable, and provided with the function oftransferring said plurality of colored toner images, which have beentransported on said toner image transporting belt, onto said recordmedium and forming a composite color image.
 9. The image forming deviceaccording to claim 8,wherein said plurality of colored toner images haveat least two colors selected from the group consisting of cyan, magenta,yellow and black.
 10. The image forming device according to claim8,wherein said plurality of colored toner images have at least twocolors selected from the group consisting of two kinds of cyan with thedarkness thereof differing from each other and two kinds of magenta withthe darkness thereof differing from each other.
 11. An image formingdevice comprising:(a) a loop-like belt shaped toner image transportingbelt for transporting a toner image, said toner image transporting beltbeing installed so as to be rotatable in the same direction as a recordmedium is transported; (b) a plurality of rollers that support and makerotatable said toner image transporting belt; (c) a plurality of tonerattaching means that moves toward said toner image transporting beltalong the rotational direction of said toner image transporting belt soas to have a plurality of colored toner image, each of which has a colordifferent from others, attached and transported on the outer surface ofsaid toner image transporting belt, for having a plurality of coloredtoner images transported; and (d) an opposed image transferring rollerinstalled on the inner side of said toner image transporting belt so asto have said toner image transporting belt pressed onto said recordmedium and to make the same moveable, and provided with the function oftransferring said plurality of colored toner images, which have beentransported on said toner image transporting belt, onto said recordmedium and forming a composite color image, wherein while the rotationof said toner image transporting belt being suspended said opposed imagetransferring roller presses said toner image transporting belt onto saidrecord medium while moving, and each respective colored toner image outof said plurality of colored toner images is transferred one afteranother onto said stationary record medium.
 12. An image forming deviceof claim 11, wherein the transferring process is repeated for eachrespective color until all colors of the plurality of colors aretransferred on said record medium, said plurality of color toner imagestransferred on said record medium are fixed by an image fixing means.13. An image forming device comprising:(a) a loop-like belt shaped tonerimage transporting belt for transporting a toner image, said toner imagetransporting belt being installed so as to be rotatable in the samedirection as a record medium is transported; (b) a plurality of rollersthat support and make rotatable said toner image transporting belt; (c)a plurality of toner attaching units that moves toward said toner imagetransporting belt along the rotational direction of said toner imagetransporting belt so as to have a plurality of colored toner images,each of which has an image developing roller and a color different fromothers, attached and transported on the outer surface of said tonerimage transporting belt, for having a plurality of colored toner imagestransported; and (e) an opposed image transferring roller installed onthe inner side of said toner image transporting belt so as to have saidtoner image transporting belt pressed onto said record medium and tomake the same movable, and provided with the function of transferringsaid plurality of colored toner images, which have been transported onsaid toner image transporting belt, onto said record medium and forminga composite color image, wherein at least one of said plurality of tonerattaching units is installed in such a way as being detachable andattachable and while the rotation of said toner image transporting beltis suspended said opposed image transferring roller presses said tonerimage transporting belt onto said record medium while moving, and eachrespective colored toner image out of said plurality of colored tonerimages is transferred one after another onto said stationary recordmedium.
 14. An image forming device of claim 13 wherein said tonerattaching units further comprises an image developing roller.
 15. Animage forming method comprising the steps of:(a) having a first coloredtoner image out of a plurality of colored toner images of the colorsdifferent from one another on a surface of a rotatable loop-like tonerimage transporting belt; and (b) transferring said first colored tonerimage from said toner image transporting belt onto a record medium,while the rotation of said toner image transporting belt is suspended,by having said toner image transporting belt pressed down and moved inrolling to form a first composite color image on a surface of saidrecord medium, wherein said toner image transporting belt being maderotatable in the same direction as said record medium is transported.16. The image forming method according to claim 15, further comprisingthe steps of:(c) having a second colored toner image out of saidplurality of colored toner images on said surface of said toner imagetransporting belt; (d) transferring said second colored toner image fromsaid toner image transporting belt onto said record medium so as to besuperimposed on said first composite color image, while said rotation ofsaid toner image transporting belt being suspended, by having said tonerimage transporting belt pressed down and moved in rolling to form asecond composite color image on said surface of said record medium; (e)having a third colored toner image out of said plurality of coloredtoner images on said surface of said toner image transporting belt; and(f) transferring said third colored toner image from said toner imagetransporting belt onto said record medium so as to be superimposed onsaid second composite color image, while said rotation of said tonerimage transporting belt being suspended, by having said toner imagetransporting belt pressed down and moved in rolling to form a thirdcomposite color image on said surface of said record medium.
 17. Theimage forming method according to claim 16, further comprising the stepsof:(g) having a fourth colored toner image out of said plurality ofcolored toner images on said surface of said toner image transportingbelt; and (h) transferring said fourth colored toner image from saidtoner image transporting belt onto said record medium so as to besuperimposed on said third composite color image, while said rotation ofsaid toner image transporting belt being suspended, by having said tonerimage transporting belt pressed down and moved in rolling to form afourth composite color image on said surface of said record medium. 18.The image forming method according to claim 15, further comprising thesteps of:(c) transporting a second colored toner image out of saidplurality of colored toner images on said surface of said toner imagetransporting belt; (d) transferring said second colored toner image fromsaid toner image transporting belt onto said record medium so as to besuperimposed on said first composite color image, while said rotation ofsaid toner image transporting belt being suspended, by having said tonerimage transporting belt pressed down and moved in rolling to form asecond composite color image on said surface of said record medium; and(e) forming a composite color image on said surface of said recordmedium by repeating said step (c) and step (d) multiple times.
 19. Theimage forming method according to claim 18, wherein said plurality ofcolored toner images have at least one color selected from the groupconsisting of a plurality of kinds of cyan with the darkness thereofdiffering from one another and a plurality of kinds of magenta, yellowand black with the darkness thereof differing from one another.
 20. Theimage forming method according to claim 15,wherein each respective colorof said plurality of colored toner images has at least one colorselected from the group consisting of cyan, magenta, yellow and black.21. The image forming method according to claim 15,wherein eachrespective colored toner image of said plurality of colored toner imagesis transferred onto said record medium that is standing still.
 22. Theimage forming method according to claim 15,further comprising the stepof fixing said first composite color image, third composite color image,fourth composite color image and one out of said composite color images.23. An image forming method of claim 13, further comprising the stepsof;(c) repeating the transferring process of steps (a) and (b) for eachof the respective colors of the plurality of colors until the number ofcolors required to form a color image on said record medium is complete,and (d) fixing said color image transferred on said record medium by animage fixing means.